The present invention relates to a method of sterilizing fungi and/or bacteria in a spore state for sterilizing fungi and/or bacteria in a spore state, as sterilization targets, which are adhering to target-adhering things such as containers, packing materials, conveying tools, etc. or contained in target-containing things such as liquid, air, raw materials, etc. and a sterilizer of thereof.
Sterilization of fungi adhering on the surface of containers has so far been effected by irradiating ultraviolet rays over the containers when filling them up with contents such as drinks, pharmaceutical, industrial products, cosmetics before or after filling up. As a method of sterilizing fungi adhering to the containers, there are generally well known various applications such as ultraviolet rays sterilization by irradiation of ultraviolet rays, thermal sterilization by thermal application with hot water, heated steam, etc. or chemical sterilization by application of chemicals.
However, while conventional applications such as ultraviolet rays sterilization, thermal sterilization or chemical sterilization are effective only against some of the fungi, there is a problem that a satisfactory effect against other fungi cannot be expected by these applications.
Some fungi show strong tolerance against ultraviolet rays. Examples of these fungi are Chaetomium, Aspergillus and so on. Chaetomium and Aspergillus have the nature that they are strong against ultraviolet rays and also tolerant to some extent against heat, and in addition they show such powerful cellulolytic activity that ATCC 6205 strain is specified as one of the test fungi for fungicides by Japanese Industrial Standards (JIS).
Chaetomium and Aspergillus inhabit paper, pulp, vinyl, wood, etc. in addition to foods such as cereals, margarine and so on or dead leaves and soil by sticking. Their habitation distribution is global, and they are found all over Japan.
Further, there are known Bacillus subtilis and the like forming a spore as bacteria which are resistant to heat, though they are not classified as fungi. As a result of investigations and studies, the inventor of the present invention has found that bacteria in this spore state are very strong against heat but comparatively vulnerable to ultraviolet rays.
These Chaetomium, Aspergillus and bacteria in the spore state easily adhere to a container, a wrapping paper, a packing bag and so on because they are contained in dirty atmosphere as well as in soil, dirty water, and the like. In particular when a containers wears static electricity, its adhesive power is so strong that it is necessary to sterilize the container in order to employ the container in a hygienic state.
Therefore, the containers used for packing medical supplies, foods or the like are generally sterilized beforehand by means of ultraviolet rays or heat before filling up the containers with the contents in the filling room.
In the case where a product is to be manufactured by mass production, a method of previously producing a large number of containers and then conveying the necessary number of containers into the filling room is often adopted. A large number of containers are filled in cardboard boxes, kept in the safekeeping storage, conveyed in a encased state on a production line, picked up from the boxes onto a line conveyer and conveyed into a filling room. Therefore, when, for example, Chaetomium adheres to a cardboard container and proliferates there, the fungi may adhere to a container and are supplied on a production line.
Thus, the sterilization of a container has been performed before filling up a container by a filling device. However, Chaetomium, Aspergillus and so on are only hurt by conventional sterilization such as a method of merely irradiating ultraviolet rays or a method of merely heating, so that these fungi may not be killed completely, and sufficient sterilization of the container is not conducted.
As a result, there is a possibility that contents would be polluted through the container and the like by filling up the contents into the container with Chaetomium and the like adhering when filling up the contents into the container by a filling device. Further, there are possibilities that Chaetomium and the like move from the container into the filling room and that the filling room would be polluted with Chaetomium and the like, when the container is conveyed into the filling room.
Thus, the present invention has been established in view of these conventional problems. An object of the invention is to provide a method of sterilizing fungi and bacteria in a spore state and a sterilizer therefor which comprises enabling to sterilize fungi and bacteria in a spore state by irradiating ultraviolet rays over them to hurt them and heating the fungi and the like, or heating the fungi and the like and then irradiating ultraviolet rays over them, as a combination of UV radiation and heating, neither UV radiation only nor heating only.
The present invention is directed to a method of sterilizing fungi and/or bacteria in a spore state which comprises irradiating ultraviolet rays over the portions to be sterilized on target-adhering things such as containers, packing materials, conveying tools, etc. and on target-containing things such as liquid, air, raw materials, etc. to hurt sterilization targets such as fungi and/or bacteria in a spore state, which adhere to the target-adhering things or are contained in the target-containing things, and then heating the sterilization targets for sterilization.
Further, the present invention concerns a method of sterilizing fungi and/or bacteria in a spore state which comprises heating portions to be sterilized on target-adhering things such as containers, packing materials, conveying tools, etc. and on target-containing things such as liquid, air, raw materials, etc. to give thermal stimulation to the sterilization targets such as fungi and/or bacteria in a spore state, which adhere to the target-adhering things or contained in the target-containing things and then irradiating ultraviolet rays over the sterilization targets for sterilization.
In addition, the invention concerns a sterilizer of fungi and bacteria in a spore state which comprises UV radiation means for irradiating ultraviolet rays over portions to be sterilized on target-adhering things such as containers, packing materials, conveying tools, etc. or on target-containing things such as liquid and raw materials, etc. to hurt sterilization targets such as fungi and/or bacteria in a spore state, which adhere to the target-adhering things or are contained in the target-containing things, and heating means for heating the sterilization targets having wounds produced by UV radiation.
Furthermore, this invention relates to a sterilizer of fungi and bacteria in a spore state which comprises heating means for heating portions to be sterilized on target-adhering things such as containers, packing materials, conveying tools, etc. or on target-containing things such as liquid and raw materials, etc. to give thermal stimulation to sterilization targets such as fungi and/or bacteria in a spore state, which adhere to the target-adhering things or are contained in the target-containing things, and UV radiation means to irradiate ultraviolet rays over the sterilization targets having received the thermal stimulation.